Yes so jumper cables are pair of insulated electric wires having crocodile clips at each end and used for starting the engine of a vehicle whose battery is dead.
yes so if you don't want to be ever stranded,then pls treat it as a rule to always get or have one in your car as on the road most passing by cars will only help you start your car on the condition of you having jumper cabbles,this is because they see it as total waste of time when you ask them to borrow you their batteries by removing it from their car.